Refactor: Run before and after script of container runner inside the …

…container using host runner Signed-off-by: GLVS Kiriti <[email protected]>
falcosecurity · Aug 1, 2024 · d8baeb5 · d8baeb5
1 parent 0c38982
commit d8baeb5
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Showing 4 changed files with 30 additions and 80 deletions.
diff --git a/cmd/declarative.go b/cmd/declarative.go
@@ -79,6 +79,9 @@ func runTestSteps(test declarative.Test) error {
 		// spawn an alpine container
 		runner = &declarative.Containerrunner{Image: "golang"}
 		ctx = context.Background()
+		ctx = context.WithValue(ctx, declarative.ContextKey("ruleName"), test.Rule)
+		ctx = context.WithValue(ctx, declarative.ContextKey("beforeScript"), test.Before)
+		ctx = context.WithValue(ctx, declarative.ContextKey("afterScript"), test.After)
 	default:
 		return fmt.Errorf("unsupported runner: %v", test.Runner)
 	}
@@ -89,11 +92,9 @@ func runTestSteps(test declarative.Test) error {
 	}
 
 	// Execute each step in the test.
-	for _, step := range test.Steps {
-		err := runner.ExecuteStep(ctx, step)
-		if err != nil {
-			return fmt.Errorf("error executing steps for the rule %v : %v", test.Rule, err)
-		}
+	err := runner.ExecuteStep(ctx, test.Steps)
+	if err != nil {
+		return fmt.Errorf("error executing steps for the rule %v : %v", test.Rule, err)
 	}
 
 	// Execute the "After" script.

diff --git a/pkg/declarative/container.go b/pkg/declarative/container.go
@@ -20,6 +20,7 @@ import (
 	"io"
 	"log"
 	"os"
+	"path/filepath"
 
 	"github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/api/types/image"
@@ -86,50 +87,10 @@ func (r *Containerrunner) Setup(ctx context.Context, beforeScript string) error
 	if err != nil {
 		return fmt.Errorf("error starting Docker container: %v", err)
 	}
-
-	// Run beforescript
-	cmd := []string{"sh", "-c", beforeScript}
-
-	execConfig := container.ExecOptions{
-		Cmd: cmd,
-	}
-
-	execID, err := cli.ContainerExecCreate(ctx, r.ContainerId, execConfig)
-	if err != nil {
-		return fmt.Errorf("error creating Docker exec: %v", err)
-	}
-
-	err = cli.ContainerExecStart(ctx, execID.ID, container.ExecStartOptions{})
-	if err != nil {
-		return fmt.Errorf("error starting Docker exec: %v", err)
-	}
-
-	// Use this channel to wait for the exec instance to complete i.e, beforescript
-	done := make(chan error, 1)
-	go func() {
-		for {
-			inspectResp, err := cli.ContainerExecInspect(ctx, execID.ID)
-			if err != nil {
-				done <- fmt.Errorf("error inspecting Docker exec: %v", err)
-				return
-			}
-
-			if !inspectResp.Running {
-				if inspectResp.ExitCode != 0 {
-					done <- fmt.Errorf("before execution failed with exit code %v", inspectResp.ExitCode)
-				} else {
-					done <- nil
-				}
-				return
-			}
-		}
-	}()
-
-	err = <-done
-	return err
+	return nil
 }
 
-func (r *Containerrunner) ExecuteStep(ctx context.Context, step SyscallStep) error {
+func (r *Containerrunner) ExecuteStep(ctx context.Context, steps []SyscallStep) error {
 	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
 	if err != nil {
 		return fmt.Errorf("error creating Docker Client: %v", err)
@@ -139,11 +100,11 @@ func (r *Containerrunner) ExecuteStep(ctx context.Context, step SyscallStep) err
 	testFile := Tests{
 		Tests: []Test{
 			{
-				Rule:   "any-name",
+				Rule:   ctx.Value(ContextKey("ruleName")).(string),
 				Runner: "HostRunner",
-				Before: "",
-				Steps:  []SyscallStep{step},
-				After:  "",
+				Before: ctx.Value(ContextKey("beforeScript")).(string),
+				Steps:  steps,
+				After:  ctx.Value(ContextKey("afterScript")).(string),
 			},
 		},
 	}
@@ -173,13 +134,14 @@ func (r *Containerrunner) ExecuteStep(ctx context.Context, step SyscallStep) err
 		return fmt.Errorf("error creating tar reader: %v", err)
 	}
 
-	err = cli.CopyToContainer(ctx, r.ContainerId, "/syscall.yaml", tarReader, container.CopyToContainerOptions{})
+	err = cli.CopyToContainer(ctx, r.ContainerId, "/", tarReader, container.CopyToContainerOptions{})
 	if err != nil {
 		return fmt.Errorf("error copying yaml file to container: %v", err)
 	}
 
-	// Prepare the command to run the event-generator with the write syscall
-	cmd := []string{"./event-generator", "run", "declarative", "/syscall.yaml"}
+	// Prepare the command to run the event-generator inside container
+	yamlFileName := filepath.Base(tempFile.Name())
+	cmd := []string{"/event-generator", "run", "declarative", "/" + yamlFileName}
 
 	execConfig := container.ExecOptions{
 		Cmd:          cmd,
@@ -228,24 +190,6 @@ func (r *Containerrunner) Cleanup(ctx context.Context, afterScript string) error
 		return fmt.Errorf("error creating Docker Client: %v", err)
 	}
 
-	// If there is any afterScript execute it before removing the container
-	if afterScript != "" {
-		cmd := []string{"sh", "-c", afterScript}
-		execConfig := container.ExecOptions{
-			Cmd: cmd,
-		}
-
-		execID, err := cli.ContainerExecCreate(ctx, r.ContainerId, execConfig)
-		if err != nil {
-			return fmt.Errorf("error creating Docker exec: %v", err)
-		}
-
-		err = cli.ContainerExecStart(ctx, execID.ID, container.ExecStartOptions{})
-		if err != nil {
-			return fmt.Errorf("error starting Docker exec: %v", err)
-		}
-	}
-
 	err = cli.ContainerRemove(ctx, r.ContainerId, container.RemoveOptions{Force: true})
 	if err != nil {
 		return fmt.Errorf("error removing Docker container: %v", err)

diff --git a/pkg/declarative/host.go b/pkg/declarative/host.go
@@ -31,14 +31,16 @@ func (r *Hostrunner) Setup(ctx context.Context, beforeScript string) error {
 	return nil
 }
 
-func (r *Hostrunner) ExecuteStep(ctx context.Context, step SyscallStep) error {
-	switch step.Syscall {
-	case "write":
-		if err := WriteSyscall(step.Args["filepath"], step.Args["content"]); err != nil {
-			return fmt.Errorf("write syscall failed with error: %v", err)
+func (r *Hostrunner) ExecuteStep(ctx context.Context, steps []SyscallStep) error {
+	for _, step := range steps {
+		switch step.Syscall {
+		case "write":
+			if err := WriteSyscall(step.Args["filepath"], step.Args["content"]); err != nil {
+				return fmt.Errorf("write syscall failed with error: %v", err)
+			}
+		default:
+			return fmt.Errorf("unsupported syscall: %s", step.Syscall)
 		}
-	default:
-		return fmt.Errorf("unsupported syscall: %s", step.Syscall)
 	}
 	return nil
 }

diff --git a/pkg/declarative/interface.go b/pkg/declarative/interface.go
@@ -19,6 +19,9 @@ import "context"
 // Common runner interface for runners like hostrunner, container-runner etc..
 type Runner interface {
 	Setup(ctx context.Context, beforeScript string) error
-	ExecuteStep(ctx context.Context, step SyscallStep) error
+	ExecuteStep(ctx context.Context, steps []SyscallStep) error
 	Cleanup(ctx context.Context, afterScript string) error
 }
+
+// A type which helps to store and retrive key-value pairs in context
+type ContextKey string